1. Field of the Invention
The present invention relates to a printed circuit board (PCB), and more particularly to a printed circuit board, in which a semiconductor chip is directly mounted on a heat sink panel including an integrally formed ground plane, a method for manufacturing the printed circuit board, and a semiconductor package including the printed circuit board.
2. Background of the Related Art
Many semiconductor chips generate heat during operation. Semiconductor chips, which are used in high frequency and have large scale integrated circuits, generate a larger amount of heat during operation. The heat generated must be dissipated outside the semiconductor chip. Therefore, a heat sink is attached to an electronic package in order to dissipate the heat generated to the outside.
FIG. 1 is a schematic diagram that shows a package 1 using a related art printed circuit board 2. The package 1 is generally referred to as a Ball Grid Array (BGA) package. As shown in FIG. 1, the package 1 includes a semiconductor chip 3 is mounted on the printed circuit board 2. The semiconductor chip 3 is molded with a sealant 4 for protection from the surrounding environment. Solder balls 5 are attached to the lower surface of the printed circuit board 2. The solder balls 5 serve to transmit signals and power from an external device. The semiconductor chip 3 is electrically coupleed to the printed circuit board 2 by gold wires 6 to transmit electrical signals between the semiconductor chip 3 and the printed circuit board 2.
A heat sink 7 is mounted on the upper surface of the semiconductor chip 3. The heat sink 7 serves to dissipate heat generated from the semiconductor chip 3 into the outside. The heat sink 7 is made of thermally conductive metal such as aluminum or the like. A lower surface of the heat sink 7 is attached to the upper surface of the semiconductor chip 3. An upper surface of the heat sink 7 is exposed to the outside. To more effectively dissipate the heat generated into the outside, a plurality of dissipation protrusions 8 may be formed on the upper surface of the heat sink 7, which have a large surface area, to dissipate the heat into the outside.
A large number of functional devices are integrated on the small-sized semiconductor chip 3. Therefore, much heat is generated from the semiconductor chip 3 during operation. The heat sink 7 is used to dissipate the generated heat.
If the heat is not properly dissipated, electrons are excited by this heat. Then, the semiconductor chip 3 cannot exhibit its specific performance. Therefore, the heat sink 7 must be used to dissipate the heat generated from the chip 3 into the outside.
However, as described above, the related art package provided with the heat sink has various problems. Since the heat sink 7 is formed separately from the printed circuit board 2, the heat sink 7 is attached to the printed circuit board 2 to form the package 1. Therefore, the height of the package 1 is increased. Further, it is difficult to miniaturize the package 1. In manufacturing the printed circuit board 2, a ground plane for grounding circuits formed on the printed circuit board 2 must be additionally formed. The additional ground plane increases the number of layers of the printed circuit board 2 and the height of the package 1 using the printed circuit board 2.
When the printed circuit board 2 having the semiconductor chip 3 becomes multi-layered, the height of the printed circuit board 2 is increased, which increases the height of the package 1 using the printed circuit board 2. In addition, when using the multi-layered printed circuit board, through holes for coupling the solder balls to the ground plane are required. The through holes are formed by perforating the printed circuit board. The through holes are coupled to the ground plane. Therefore, the printed circuit board requires increased or large areas for forming the through holes, which also limits variety in designing the printed circuit board.
In cases where a heat dissipation layer of the multi-layered printed circuit board is not directly connected to the semiconductor chip, through holes for transmitting the heat generated from the chip to the heat dissipation layer are also required. Of course, the related art printed circuit board requires additional areas for forming the through holes for transmitting the heat, which also limits the variety in designing the printed circuit board.
The above references are incorporated by reference herein where appropriate for appropriate teachings of additional or alternative details, features and/or technical background.